1. Write out the balanced equation for the oxidation ofhydrobromic acid by hydrogen peroxide.
2. How many stereoisomers of stilbene dibromide can exist?
3. A possible definition of a meso compound is: “while possessing 2or more assignable
stereocenters, a meso compound is superimposable (identical to) itsmirror image in at least
one conformation”. In other words, it is identical to its would-beenantiomer except for the fact
that the molecule contains… what? What physical characteristicarises in meso compounds
that results in the above definition?
4. Let us assume a cut-and-dry, black-and-white case that themechanism does only one of 2
things when each molecule of product is produced: (1) goes entirelybromonium-ion/antiaddition;
or (2) goes through a fully-fledged planar carbocation intermediatewith absolutely
no selectivity.
a. If you were to find by quantitative analysis that exactly 50% ofyour product mixture
was the meso stilbene dibromide and the other 50% was racemicstilbene dibromide,
then is mechanism case (1) or (2) favored? If so, qualitatively, byhow much?
b. Think again. Question (a) is a mind-bender. I want to know whatyou originally /
immediately thought, and what you eventually came to. If they arenot different, you
are either a genius or need to think more. Write out all thepossibilities…
c. If you find, qualitatively, that >95% of the product is meso,what does this imply about
the mechanism? What percent of the time does the mechanism go byscenario (1)…
greater than what number?
5. Describe a more likely blend of mechanisms that could haveproduced your estimated product
distribution